What is the ratio for cosine?

The cosine ratio is a trigonometric function that describes the ratio of the length of the adjacent side to the hypotenuse in a right triangle. It is defined as the ratio of the adjacent side to the hypotenuse and can also be expressed as the reciprocal of the secant function.

The cosine function is often denoted as cos(theta) or simply cos(x), where theta is the angle in radians and x is the angle in degrees. The cosine function has a range of values between -1 and 1, inclusive, and is periodic with a period of 2π.

In practical applications, the cosine ratio is used in various fields such as physics, engineering, and mathematics to solve problems involving angles and distances in right-angled triangles. It helps in calculating the lengths of sides and determining the angles of a triangle based on the known lengths of sides.